This invention relates generally to pinion gears, and more particularly to medium-sized pinion gears having high precision tooth surfaces formed by injection molding techniques.
Heretofore, medium-sized high precision pinion gears have been formed utilizing time consuming and expensive precision machining methods. Attempts at reducing the cost of producing such pinion gears by molding the gears of plastic have been generally successful for gears having a diameter of approximately 1 inch or less, but for gears of larger sizes, e.g. from 1 to 6 inches in diameter, the uneven shrinkage of the molded plastic has prevented the formation of gear teeth with the necessary precision.
With the increasing demand for economical high precision medium-sized gears, a need has arisen for a pinion gear structure which can be produced at lower cost by inexpensive injection molding methods. The present invention is directed to such a pinion gear structure.
It is therefore an object of the present invention to provide a medium size pinion gear having high precision gear teeth formed thereon by less expensive means than present metal machining methods.
It is another object of the invention to provide a high precision pinion gear wherein the gear teeth are formed of plastic by injection molding techniques.